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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

21795 results found.

  1. GRB020813: Fading X-ray Afterglow Observed with Chandra
  2. GRB020813, UBVRI field calibration
  3. Polarimetry of GRB020813: evidence for variability
  4. GRB020812: optical observations
  5. GRB020813: High-Resolution Optical Observations
  6. GRB 020812: optical observation at Bisei
  7. GRB020812: optical observations
  8. GRB020813, optical observations
  9. GRB020813, astrometric position
  10. GRB 020812 optical observation
  11. GRB 020714, optical observations
  12. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  13. HST Imaging of the Host of GRB 011121
  14. GRB020801, optical afterglow candidate
  15. GRB020331: Late-time Optical Light Curve (re-submission)
  16. GRB020331: Late-time Optical Light Curve
  17. IPN triangulation of GRB020714
  18. IPN triangulation of GRB150702
  19. GRB 020410: Discovery of Probable OT by HST
  20. IPN triangulation of GRB020708
  21. IPN triangulation of GRB020708
  22. Correction to IPN error box for GRB020706
  23. IPN triangulation of GRB020706
  24. GRB 020705: Optical observations
  25. GRB 020625: Optical observations
  26. GRB 020531: optical photometry of Chandra sources
  27. The Probable Host Galaxy of GRB/XRF 020427
  28. GRB/XRF 020427, detection of an underlying system with the VLT
  29. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  30. AXP 1E2259+586 optical observations
  31. Fading Optical Source in the Field of GRB020531
  32. GRB 020531, INT+WFC deep optical upper limits
  33. GRB020405: polarimetric observations
  34. GRB 020531, simultaneous optical observations
  35. GRB020531: Second epoch Chandra observations
  36. GRB020604, optical observations
  37. GRB020604, BVRcIc field photometry
  38. GRB020603, BVRcIc field observations
  39. GRB020531, BVRcIc field photometry
  40. GRB 020531, Radio Observations
  41. IPN triangulation of GRB020604
  42. GRB020531 Optical Observations
  43. GRB020531: Observations with the Chandra X-ray Observatory
  44. GRB020531, optical observations
  45. GRB020531: optical observations
  46. GRB020531(=H2042): Optical Observations
  47. GRB020531(=H2042): Optical Observations
  48. GRB020525, optical observations
  49. IPN triangulation of GRB020525
  50. GRB020405 field photometry at ESO
  51. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  52. XRF 020427
  53. GRB 020124: Optical observations
  54. IPN triangulation of GRB020418
  55. GRB020405: VLT observations of the OT environment
  56. GRB020405: predicted break
  57. GRB 020409: No Evidence for an Optical Afterglow
  58. GRB 020331 Kyoto observation on March 31
  59. GRB 020409
  60. BeppoSAX ALERT: possible GRB020411
  61. X-ray afterglow of GRB020321
  62. GRB020331 optical observations with RIMOTS
  63. GRB020124 optical observations with RIBOTS/RIMOTS
  64. GRB 020321: Candidate X-ray Counterparts
  65. ASM GRB candidate 020406 refined error box
  66. GRB020406(?), optical observations
  67. Short RXTE/ASM transient 020406; may be a GRB
  68. GRB020405, Radio Observations
  69. GRB 020405, U-band observations
  70. IPN localization of GRB020405
  71. GRB020331 NIR observation at KPNO (re-submission)
  72. GRB02033 NIR observation at KPNO
  73. GRB020331 field photometry
  74. GRB 020331, NIR observations
  75. GRB 020322: BeppoSAX observations of the X-ray afterglow
  76. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  77. GRB 020322, Radio observations
  78. Near-Infrared Observations of GRB020322 at TIRGO
  79. GRB 020321, Radio Observations
  80. GRB 020322: Optical Observations
  81. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  82. GRB 020321: Optical observations
  83. GRB020317 BVRI field photometry
  84. GRB011211 revised BVRI field photometry
  85. GRB020305 BVRI field photometry
  86. GRB020322 BVRI field photometry
  87. GRB 020322: Optical Sources and Improved Astrometry
  88. GRB020317: optical observations
  89. GRB020321 optical observations
  90. GRB020321: a faint BeppoSAX detection
  91. GRB 020317 : KISO Optical Observations
  92. BeppoSAX ALERT: GRB020321, the "Springtime Burst"
  93. GRB 020305: Optical Observations
  94. GRB020317, optical observations
  95. GRB 020317: Optical observations
  96. GRB020305: Properties of the Candidate Optical Afterglow
  97. GRB 011121: HST Observations reveal an intermediate-time multicolor
  98. GRB011130 (XRF011130) Second Epoch Chandra Observations
  99. XRF/GRB 011030: Detection of the Probable Host Galaxy
  100. GRB020305, optical observations

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